Microstructure, transmittance and upconversion luminescence of Y₂O₃:Er³⁺ translucent ceramics

Y₂O₃:Er³⁺ translucent ceramics was fabricated with addition of La(OH)₃ nanopowder as a sintering aid. The influence of La(OH)₃ addition on the microstructure, transmittance and upconversion luminescence of Y₂O₃:Er³⁺ ceramics was investigated in detail. The results show that the ceramics sample with 5 mol % La(OH)₃ additives exhibits finer microstructure with fewer pores and higher optical transmittance than others. It was proved that La(OH)₃ additives could greatly reduce the porosity and improve the transparency of Y₂O₃:Er³⁺ ceramics. By using a 980 nm diode laser as a pumping source, the Y₂O₃:Er³⁺ ceramics gave bright visible upconversion luminescence, which was ascribed to the radiative transitions of ²H_11/2,⁴S_3/2 →⁴I_15/2 and ⁴F_9/2 →⁴I_15/2 of Er³⁺ ions, respectively. The possible upconversion mechanism has been proposed accordingly.